1. Field of the Invention
This invention relates to an antenna and more particularly to an enhanced antenna using flexible circuitry.
2. Description of the Related Art
Media storage systems are well known in the art and are commonly used to store data cartridges at known locations and to retrieve desired data cartridges so that data may be written to or read from the data cartridges. Such media storage systems are often referred to as an autochanger media storage system or, simply, an autochanger (“media storage system”). A typical media storage system may include one or more different types of cartridge receiving devices for holding the various data cartridges. Different cartridge receiving devices comprise an individual cartridge storage location or a slot for holding single data cartridges, or cartridge storage racks or “magazines” for holding several data cartridges. Another type of cartridge receiving device may comprise a cartridge read/write device for reading data from or writing data to the data cartridges contained in the media storage system.
The media storage system can also be provided with a cartridge handling system for transporting the data cartridges between the various cartridge receiving devices, such as between a cartridge storage rack and a read/write device. A typical cartridge handling system includes a cartridge engaging assembly known as a “picker” that engages various data cartridges contained in the cartridge receiving devices, and also includes a positioning device for moving the picker among the various data cartridges.
Media storage systems of the type described above are usually connected to a host computer system, which can access or store data on the data cartridges. For example, if the host computer system issues a request for data contained on a particular data cartridge, a control system associated with the media storage system actuates the positioning device to move the “picker” along the cartridge storage locations until the picker is positioned adjacent the desired data cartridge. The picker can then remove the data cartridge from the cartridge rack and carry it to the cartridge read/write device. Once positioned adjacent the cartridge read/write device, the picker can insert the selected data cartridge into the read/write device so that the host computer can read data from or write data to the data cartridge. After the read/write operation is complete, the picker can remove the data cartridge from the cartridge read/write device and return it to the appropriate cartridge rack.
Since most such media storage systems contain a large number of individual data cartridges, some means is usually provided to enable the media storage system to identify and communicate with the desired data cartridge. One method for identifying and communicating with the data cartridges is by radio frequency identification (RFID) technology. A reader communicates with an identification device on a data cartridge over a radio frequency communication link. Information on the data cartridge identification device can include information that uniquely identifies the data cartridge as well as data relating to the type or classification of the data contained in the cartridge.
A typical reader includes an antenna, which comprises numerous turns of a fine wire or traces to form a coil etched on a printed circuit board. The data cartridge identification device typically comprises a RFID transponder that can have its own power source or derive power from a magnetic or electric field from the reader. The transponder can communicate data by radio frequency that is relevant to its data cartridge.
The coils of a conventional RFID antenna are formed on a single side of a rigid printed circuit board (PCB) and the processing limitations of rigid PCBs cause the single sided coil to be narrow in the middle, which decreases antenna performance. If a storage/retention device is included in the middle of the coil, the number of possible turns of the coil is further reduced, which further decreases performance. Other RFID antennas are formed on double-sided rigid PCBs but the distance between the first and second coils, and materials and the processing involved, make fabricating these types of antenna prohibitively expensive.
RFID uses low power in its transmission and using a conventional antenna, the transmission range between the antenna and transponder is kept in the range of 0-3 mm. Reading from this range creates a danger of damage to the reader, picker, and date cartridge data transponder if the reader is to perform while sweeping past the cartridges. The reader can collide with one of the data cartridges when it moves.